1. Field of the Invention
The present invention relates to a structure for connecting two members, a method therefore, and a die used for the method. In particular, the invention relates to a coolant piping of an air conditioning apparatus for a vehicle which is connected to an expansion valve, or similar devices.
2. Description of the Related Art
In the technical field of an air conditioning apparatus for a vehicle, for example, coolant piping is connected between a liquid tank and a compressor, between a condenser and a liquid tank, or between an expansion valve and an evaporator. In Japanese Patent No. 2591388 publication, a structure where coolant piping is connected to a passage of a block-shaped expansion valve has been disclosed. In the case that a pipe is connected to the passage of the expansion valve, the following steps are conducted in order to provide the connection. An annular recess portion receiving a projection portion formed on an outer periphery of the pipe is first provided on an open end of the passage in the expansion valve. Further, a cylindrical wall for caulking is provided on an outer peripheral portion of the recess portion. Next, the pipe is inserted into the open end of the passage in the expansion valve. Thereby, an O-ring fitted on an outer periphery of the pipe is brought into pressure-contact with an inner periphery of the passage and the projection portion of the pipe is received in the recess portion. Next, the cylindrical wall formed on the outer periphery of the recess portion is bent inwardly to be deformed by a jig, so that the bent and deformed cylindrical wall and the projection portion are engaged with each other and the pipe and the expansion are connected to each other.
In the above-described example, however, it is necessary to cut the surface of the material of the expansion valve so as to cut out the cylindrical wall in advance by a cutting tool such as an end mill. For this reason, the cutting work results in an increased manufacturing cost.